Strange Salamander Problem

[ukrobj]

Ok, I inherited a job from a plumber that has since passed away, situation is this.

Coffin tank in the loft feeding 22mm to DHW Cylinder.
22mm gravity feed to the pump from coffin tank
22mm feed from DHW Cylinder via Essex flange to pump

15mm feeding up to a bar mixer shower and mixer tap in basin next floor up. Not sure if any non-return valves or how the pipework is arranged, however it was working fine 2 months ago and has gradually got worse recently.

Pump brand new, Salamander been out and replaced it under warranty. Said to check pipework (was 15mm feeding hot and cold to pump) I've upgraded it to 22mm as requested.

Problem: Run the shower and after 5 minutes, it redcuces to a trickle (hot wise), leave it 10 minutes and its fine again. Tried running the basin mixer and same thing happens. Starts off ok then after about 3 mins just fades to a trickle. Leave it again for 10 mins and its ok.

Tried running the basin, it fails, then open the lever arm on the hot supply of the shower for a second, then close it, re-try the basin and its fine again for 3 mins and again fails to a trickle.

Things tried or checked out:

Cold feed is supplying enough, coffin tank is filling up fast as its being used so plenty of water.

Taken supplies off pump straight to bucket and its working fine, 15 mins and filled several buckets with no problem at all.

Taken shower off wall and fitted couple of lever isolation valves, opened them and it works fine!! Leave it for 15 mins with no drop what so ever on flow or pressure.

Re-fitted shower and problem again after 3 minutes.



Fitted non-return valve in hot supply, made no difference.

Any thoughts, suggestions?

Thanks
Rob

 

[seco services]

mains maybe filling coffin tank quick enough but sounds like the 22mm to the cylinder is struggling to keep up.
up it to 28mm

 

[ukrobj]

Hi Seco, thought that also, so ran hot taps downstairs thats taken from top of cylinder and ran shower via lever arm valves which is taken from 9inches below the top, so was waiting for taps to stop downstairs if cylinder wasn't receiving enough cold water from coffin tank.

They maintained their flow, so thinking 22mm although isn't great is still keeping cylinder supplied with cold water.

 

[seco services]

does the downstairs still flow when shower stops
did you fit the non return on the outlet of the pump ?
is the essex flange a no stop flange ?

 

[ukrobj]

does the downstairs still flow when shower stops
did you fit the non return on the outlet of the pump ?
is the essex flange a no stop flange ?

Yes, still flows when shower slows to trickle.

Yes tried non return on outlet of the pump to no effect

Essex flange was from BES (www.bes.co.uk) pushed 22mm into centre of cylinder and tightened. But this was happening before this, it was connected to surrey flange. So thought it may be pulling in air hence the essex flange.

 

[seco services]

what model pump is it ?
what happened to the first pump ?

 

[picasso]

where is the pump in relation to the hot water cylinder ?

 

[ukrobj]

what model pump is it ?
what happened to the first pump ?

ESP 50 CPV twin

Customer called Salamander first, they came out and just replaced the pump, no questions asked. They advised to upgrade the inlet from 15mm to 22mm, which was when I was called in.

But this didn't resolve the issue either.

 

[seco services]

can't get my head round this bit.

>Tried running the basin, it fails, then open the lever arm on the hot supply of the shower for a second, then close it, re-try the basin and its fine again for 3 mins and again fails to a trickle.

 

[ukrobj]

can't get my head round this bit.

>Tried running the basin, it fails, then open the lever arm on the hot supply of the shower for a second, then close it, re-try the basin and its fine again for 3 mins and again fails to a trickle.

Welcome to my world!

The thing is, when the basin fails (left on hot only) I only have to open the lever arm on the hot supply in the shower cubicle for a second and then close it again and the basin flow returns to normal.

 

[ukrobj]

where is the pump in relation to the hot water cylinder ?

Right next to the cylinder, on the floor.

 

[seco services]

need a pic of the layout really.

 

[ukrobj]

View media item 20551
I know its a bit basic, but is that any help?

 

[dazza87]

turn the stat down on cylinder got to be a overheat problem then try it

 

[Richard C]

Got me thinking now; can you elaborate on the diagram a bit more with some approximate vertical dimensions realative to the cws tank; include the shower head & taps. Are there up & over loops feeding the shower head & do they have vents?